diff --git a/Kernel_23/include/CGAL/Kernel/function_objects.h b/Kernel_23/include/CGAL/Kernel/function_objects.h
index 40d05f8094d..06758a7d7a3 100644
--- a/Kernel_23/include/CGAL/Kernel/function_objects.h
+++ b/Kernel_23/include/CGAL/Kernel/function_objects.h
@@ -53,7 +53,7 @@ namespace CommonKernelFunctors {
         return 0;
       } else if(certainly_not(is_zero(vec.y()))){
         return 1;
-      }else if(certainly_not(is_zero(vec.y()))){
+      }else if(certainly_not(is_zero(vec.z()))){
         return 2;
       }